Synonyms

Historical Background

The mixed-lineage kinases are so named for their sequence similarity to both tyrosine kinases and serine/threonine kinases. However, based on biochemical assays, only serine/threonine kinase activity has been demonstrated for the MLKs. The three subfamilies of MLKs reside within the “tyrosine kinase-like” branch of the human kinome. Members of the MLK subfamily, comprised of MLK1-4, share a conserved domain arrangement and 75% identity within their catalytic domains (Fig.
1). The dual leucine zipper–bearing kinase (DLK) subgroup of MLKs, which includes DLK/ZPK/MUK and LZK, is characterized by a kinase catalytic domain followed by two leucine zipper motifs. A third subgroup of MLKs represented by ZAK/MLTK contains both a leucine zipper motif and a sterile-alpha motif. MLK3 has emerged as the paradigm for the MLK...